import { logging, normalize, virtualFs } from '@angular-devkit/core';
import { NodeJsSyncHost } from '@angular-devkit/core/node';
import { BaseWorkflow } from '@angular-devkit/schematics/src/workflow';
import { NodeModulesEngineHost } from '@angular-devkit/schematics/tools';
import { execSync } from 'child_process';
import { readFileSync, writeFileSync } from 'fs';
import { dirname, extname, join, resolve } from 'path';
import { gt, lte } from 'semver';
import * as stripJsonComments from 'strip-json-comments';
import { dirSync } from 'tmp';
import { getLogger } from '../shared/logger';
import { convertToCamelCase, handleErrors } from '../shared/params';
import minimist = require('minimist');
import { NodePackageName } from '@angular-devkit/schematics/tasks/node-package/options';
import { TaskExecutor } from '@angular-devkit/schematics';
import { BuiltinTaskExecutor } from '@angular-devkit/schematics/tasks/node';

export type MigrationsJson = {
  version: string;
  schematics?: { [name: string]: { version: string } };
  packageJsonUpdates?: {
    [name: string]: {
      version: string;
      packages: {
        [p: string]: {
          version: string;
          ifPackageInstalled?: string;
          alwaysAddToPackageJson?: boolean;
        };
      };
    };
  };
};

export class Migrator {
  private readonly versions: (p: string) => string;
  private readonly fetch: (p: string, v: string) => Promise<MigrationsJson>;
  private readonly from: { [p: string]: string };
  private readonly to: { [p: string]: string };

  constructor(opts: {
    versions: (p: string) => string;
    fetch: (p: string, v: string) => Promise<MigrationsJson>;
    from: { [p: string]: string };
    to: { [p: string]: string };
  }) {
    this.versions = opts.versions;
    this.fetch = opts.fetch;
    this.from = opts.from;
    this.to = opts.to;
  }

  async updatePackageJson(targetPackage: string, targetVersion: string) {
    const packageJson = await this._updatePackageJson(
      targetPackage,
      { version: targetVersion, alwaysAddToPackageJson: false },
      {}
    );
    const migrations = await this._createMigrateJson(packageJson);
    return { packageJson, migrations };
  }

  private async _createMigrateJson(versions: {
    [k: string]: { version: string; alwaysAddToPackageJson: boolean };
  }) {
    const migrations = await Promise.all(
      Object.keys(versions).map(async c => {
        const currentVersion = this.versions(c);
        if (currentVersion === null) return [];

        const target = versions[c];
        const migrationsJson = await this.fetch(c, target.version);
        if (!migrationsJson.schematics) return [];
        return Object.keys(migrationsJson.schematics)
          .filter(
            r =>
              this.gt(migrationsJson.schematics[r].version, currentVersion) &
              this.lte(migrationsJson.schematics[r].version, target.version)
          )
          .map(r => ({
            ...migrationsJson.schematics[r],
            package: c,
            name: r
          }));
      })
    );

    return migrations.reduce((m, c) => [...m, ...c], []);
  }

  private async _updatePackageJson(
    targetPackage: string,
    target: { version: string; alwaysAddToPackageJson: boolean },
    collectedVersions: {
      [k: string]: { version: string; alwaysAddToPackageJson: boolean };
    }
  ) {
    let targetVersion = target.version;
    if (this.to[targetPackage]) {
      targetVersion = this.to[targetPackage];
    }

    if (!this.versions(targetPackage)) {
      return {
        [targetPackage]: {
          version: target.version,
          alwaysAddToPackageJson: !!target.alwaysAddToPackageJson
        }
      };
    }

    let migrationsJson;
    try {
      migrationsJson = await this.fetch(targetPackage, targetVersion);
      targetVersion = migrationsJson.version;
    } catch (e) {
      if (e.message.indexOf('No matching version') > -1) {
        throw new Error(
          `${e.message}\nRun migrate with --to="package1@version1,package2@version2"`
        );
      } else {
        throw e;
      }
    }
    const packages = this.collapsePackages(
      targetPackage,
      targetVersion,
      migrationsJson
    );

    const childCalls = await Promise.all(
      Object.keys(packages)
        .filter(r => {
          return (
            !collectedVersions[r] ||
            this.gt(packages[r].version, collectedVersions[r].version)
          );
        })
        .map(u =>
          this._updatePackageJson(u, packages[u], {
            ...collectedVersions,
            [targetPackage]: target
          })
        )
    );
    return childCalls.reduce(
      (m, c) => {
        Object.keys(c).forEach(r => {
          if (!m[r] || this.gt(c[r].version, m[r].version)) {
            m[r] = c[r];
          }
        });
        return m;
      },
      {
        [targetPackage]: {
          version: migrationsJson.version,
          alwaysAddToPackageJson: target.alwaysAddToPackageJson || false
        }
      }
    );
  }

  private collapsePackages(
    packageName: string,
    targetVersion: string,
    m: MigrationsJson | null
  ) {
    // this should be used to know what version to include
    // we should use from everywhere we use versions

    if (packageName === '@nrwl/workspace') {
      if (!m.packageJsonUpdates) m.packageJsonUpdates = {};
      m.packageJsonUpdates[targetVersion + '-defaultPackages'] = {
        version: targetVersion,
        packages: [
          '@nrwl/angular',
          '@nrwl/cypress',
          '@nrwl/eslint-plugin-nx',
          '@nrwl/express',
          '@nrwl/jest',
          '@nrwl/linter',
          '@nrwl/nest',
          '@nrwl/next',
          '@nrwl/node',
          '@nrwl/nx-plugin',
          '@nrwl/react',
          '@nrwl/storybook',
          '@nrwl/tao',
          '@nrwl/web'
        ].reduce(
          (m, c) => ({
            ...m,
            [c]: { version: targetVersion, alwaysAddToPackageJson: false }
          }),
          {}
        )
      };
    }
    if (!m.packageJsonUpdates || !this.versions(packageName)) return {};

    return Object.keys(m.packageJsonUpdates)
      .filter(r => {
        return (
          this.gt(
            m.packageJsonUpdates[r].version,
            this.versions(packageName)
          ) && this.lte(m.packageJsonUpdates[r].version, targetVersion)
        );
      })
      .map(r => m.packageJsonUpdates[r].packages)
      .map(packages => {
        if (!packages) return {};

        return Object.keys(packages)
          .filter(
            p =>
              !packages[p].ifPackageInstalled ||
              this.versions(packages[p].ifPackageInstalled)
          )
          .reduce(
            (m, c) => ({
              ...m,
              [c]: {
                version: packages[c].version,
                alwaysAddToPackageJson: packages[c].alwaysAddToPackageJson
              }
            }),
            {}
          );
      })
      .reduce((m, c) => ({ ...m, ...c }), {});
  }

  private gt(v1: string, v2: string) {
    return gt(normalizeVersion(v1), normalizeVersion(v2));
  }

  private lte(v1: string, v2: string) {
    return lte(normalizeVersion(v1), normalizeVersion(v2));
  }
}

function normalizeVersionWithTagCheck(version: string) {
  if (version === 'latest' || version === 'next') return version;
  return normalizeVersion(version);
}

export function normalizeVersion(version: string) {
  const [v, t] = version.split('-');
  const [major, minor, patch] = v.split('.');
  const newV = `${major || 0}.${minor || 0}.${patch || 0}`;
  const newVersion = t ? `${newV}-${t}` : newV;

  try {
    gt(newVersion, '0.0.0');
    return newVersion;
  } catch (e) {
    try {
      gt(newV, '0.0.0');
      return newV;
    } catch (e) {
      const withoutPatch = `${major || 0}.${minor || 0}.0`;
      try {
        if (gt(withoutPatch, '0.0.0')) {
          return withoutPatch;
        }
      } catch (e) {
        const withoutPatchAndMinor = `${major || 0}.0.0`;
        try {
          if (gt(withoutPatchAndMinor, '0.0.0')) {
            return withoutPatchAndMinor;
          }
        } catch (e) {
          return '0.0.0';
        }
      }
    }
  }
}

type GenerateMigrations = {
  type: 'generateMigrations';
  targetPackage: string;
  targetVersion: string;
  from: { [k: string]: string };
  to: { [k: string]: string };
};
type RunMigrations = { type: 'runMigrations'; runMigrations: string };

export function parseMigrationsOptions(
  args: string[]
): GenerateMigrations | RunMigrations {
  const options = convertToCamelCase(
    minimist(args, {
      string: ['runMigrations', 'from', 'to'],
      alias: {
        runMigrations: 'run-migrations'
      }
    })
  );
  if (!options.runMigrations) {
    const from = options.from ? versionOverrides(options.from, 'from') : {};
    const to = options.to ? versionOverrides(options.to, 'to') : {};
    const { targetPackage, targetVersion } = parseTargetPackageAndVersion(
      args[0]
    );
    return {
      type: 'generateMigrations',
      targetPackage,
      targetVersion,
      from,
      to
    };
  } else {
    return { type: 'runMigrations', runMigrations: options.runMigrations };
  }
}

function parseTargetPackageAndVersion(args: string) {
  if (!args) {
    throw new Error(
      `Provide the correct package name and version. E.g., @nrwl/workspace@9.0.0.`
    );
  }

  if (args.indexOf('@') > -1) {
    const i = args.lastIndexOf('@');
    if (i === 0) {
      const targetPackage = args.trim();
      const targetVersion = 'latest';
      return { targetPackage, targetVersion };
    } else {
      const targetPackage = args.substring(0, i);
      const maybeVersion = args.substring(i + 1);
      if (!targetPackage || !maybeVersion) {
        throw new Error(
          `Provide the correct package name and version. E.g., @nrwl/workspace@9.0.0.`
        );
      }
      const targetVersion = normalizeVersionWithTagCheck(maybeVersion);
      return { targetPackage, targetVersion };
    }
  } else {
    if (args.match(/[0-9]/) || args === 'latest' || args === 'next') {
      return {
        targetPackage: '@nrwl/workspace',
        targetVersion: normalizeVersionWithTagCheck(args)
      };
    } else {
      return {
        targetPackage: args,
        targetVersion: 'latest'
      };
    }
  }
}

function versionOverrides(overrides: string, param: string) {
  const res = {};
  overrides.split(',').forEach(p => {
    const split = p.lastIndexOf('@');
    if (split === -1 || split === 0) {
      throw new Error(
        `Incorrect '${param}' section. Use --${param}="package@version"`
      );
    }
    const selectedPackage = p.substring(0, split).trim();
    const selectedVersion = p.substring(split + 1).trim();
    if (!selectedPackage || !selectedVersion) {
      throw new Error(
        `Incorrect '${param}' section. Use --${param}="package@version"`
      );
    }
    res[selectedPackage] = normalizeVersionWithTagCheck(selectedVersion);
  });
  return res;
}

function versions(root: string, from: { [p: string]: string }) {
  return (packageName: string) => {
    try {
      if (from[packageName]) {
        return from[packageName];
      }
      const content = readFileSync(
        join(root, `./node_modules/${packageName}/package.json`)
      );
      return JSON.parse(stripJsonComments(content.toString()))['version'];
    } catch (e) {
      return null;
    }
  };
}

// testing-fetch-start
function createFetcher(logger: logging.Logger) {
  let cache = {};
  return async function f(
    packageName: string,
    packageVersion: string
  ): Promise<MigrationsJson> {
    if (!cache[`${packageName}-${packageVersion}`]) {
      const dir = dirSync().name;
      logger.info(`Fetching ${packageName}@${packageVersion}`);
      execSync(`npm install ${packageName}@${packageVersion} --prefix=${dir}`, {
        stdio: []
      });
      const json = JSON.parse(
        stripJsonComments(
          readFileSync(
            join(dir, 'node_modules', packageName, 'package.json')
          ).toString()
        )
      );
      let migrationsFile = json['nx-migrations'] || json['ng-update'];

      // migrationsFile is an object
      if (migrationsFile && migrationsFile.migrations) {
        migrationsFile = migrationsFile.migrations;
      }

      // packageVersion can be a tag, resolvedVersion works with semver
      const resolvedVersion = json.version;

      try {
        if (migrationsFile && typeof migrationsFile === 'string') {
          const json = JSON.parse(
            stripJsonComments(
              readFileSync(
                join(dir, 'node_modules', packageName, migrationsFile)
              ).toString()
            )
          );
          cache[`${packageName}-${packageVersion}`] = {
            version: resolvedVersion,
            schematics: json.schematics,
            packageJsonUpdates: json.packageJsonUpdates
          };
        } else {
          cache[`${packageName}-${packageVersion}`] = {
            version: resolvedVersion
          };
        }
      } catch (e) {
        logger.warn(
          `Could not find '${migrationsFile}' in '${packageName}'. Skipping it`
        );
        cache[`${packageName}-${packageVersion}`] = {
          version: resolvedVersion
        };
      }
    }
    return cache[`${packageName}-${packageVersion}`];
  };
}

// testing-fetch-end

function createMigrationsFile(root: string, migrations: any[]) {
  writeFileSync(
    join(root, 'migrations.json'),
    JSON.stringify({ migrations }, null, 2)
  );
}

function updatePackageJson(
  root: string,
  updatedPackages: {
    [p: string]: { version: string; alwaysAddToPackageJson: boolean };
  }
) {
  const packageJsonPath = join(root, 'package.json');
  const json = JSON.parse(
    stripJsonComments(readFileSync(packageJsonPath).toString())
  );
  Object.keys(updatedPackages).forEach(p => {
    if (json.devDependencies && json.devDependencies[p]) {
      json.devDependencies[p] = updatedPackages[p].version;
    } else if (json.dependencies && json.dependencies[p]) {
      json.dependencies[p] = updatedPackages[p].version;
    } else if (updatedPackages[p].alwaysAddToPackageJson) {
      if (!json.dependencies) json.dependencies = {};
      json.dependencies[p] = updatedPackages[p].version;
    }
  });
  writeFileSync(packageJsonPath, JSON.stringify(json, null, 2));
}

async function generateMigrationsJsonAndUpdatePackageJson(
  logger: logging.Logger,
  root: string,
  opts: {
    targetPackage: string;
    targetVersion: string;
    from: { [p: string]: string };
    to: { [p: string]: string };
  }
) {
  try {
    logger.info(`Fetching meta data about packages.`);
    logger.info(`It may take a few minutes.`);
    const migrator = new Migrator({
      versions: versions(root, opts.from),
      fetch: createFetcher(logger),
      from: opts.from,
      to: opts.to
    });
    const { migrations, packageJson } = await migrator.updatePackageJson(
      opts.targetPackage,
      opts.targetVersion
    );
    updatePackageJson(root, packageJson);

    if (migrations.length > 0) {
      createMigrationsFile(root, migrations);

      logger.info(`The migrate command has run successfully.`);
      logger.info(`- package.json has been updated`);
      logger.info(`- migrations.json has been generated`);

      logger.info(`Next steps:`);
      logger.info(
        `- Make sure package.json changes make sense and then run 'npm install' or 'yarn'`
      );
      logger.info(`- Run 'nx migrate --run-migrations=migrations.json'`);
    } else {
      logger.info(`The migrate command has run successfully.`);
      logger.info(`- package.json has been updated`);
      logger.info(
        `- there are no migrations to run, so migrations.json has not been created.`
      );
    }
  } catch (e) {
    const startVersion = versions(root, {})('@nrwl/workspace');
    logger.error(
      `The migrate command failed. Try the following to migrate your workspace:`
    );
    logger.error(`> npm install --save-dev @nrwl/workspace@latest`);
    logger.error(
      `> nx migrate ${opts.targetPackage}@${opts.targetVersion} --from="@nrwl/workspace@${startVersion}"`
    );
    logger.error(
      `This will use the newest version of the migrate functionality, which might have your issue resolved.`
    );
    logger.error(
      `----------------------------------------------------------------------------------------------------`
    );
    throw e;
  }
}

class MigrationEngineHost extends NodeModulesEngineHost {
  private nodeInstallLogPrinted = false;

  constructor(logger: logging.Logger) {
    super();

    // Overwrite the original CLI node package executor with a new one that does basically nothing
    // since nx migrate doesn't do npm installs by itself
    // (https://github.com/angular/angular-cli/blob/5df776780deadb6be5048b3ab006a5d3383650dc/packages/angular_devkit/schematics/tools/workflow/node-workflow.ts#L41)
    this.registerTaskExecutor({
      name: NodePackageName,
      create: () =>
        Promise.resolve<TaskExecutor>(() => {
          return new Promise(res => {
            if (!this.nodeInstallLogPrinted) {
              logger.warn(
                `An installation of node_modules has been required. Make sure to run it after the migration`
              );
              this.nodeInstallLogPrinted = true;
            }

            res();
          });
        })
    });

    this.registerTaskExecutor(BuiltinTaskExecutor.RunSchematic);
  }

  protected _resolveCollectionPath(name: string): string {
    let collectionPath: string | undefined = undefined;

    if (name.startsWith('.') || name.startsWith('/')) {
      name = resolve(name);
    }

    if (extname(name)) {
      collectionPath = require.resolve(name);
    } else {
      const packageJsonPath = require.resolve(join(name, 'package.json'));
      const packageJson = require(packageJsonPath);
      let pkgJsonSchematics = packageJson['nx-migrations'];
      if (!pkgJsonSchematics) {
        pkgJsonSchematics = packageJson['ng-update'];
        if (!pkgJsonSchematics) {
          throw new Error(`Could find migrations in package: "${name}"`);
        }
      }
      if (typeof pkgJsonSchematics != 'string') {
        pkgJsonSchematics = pkgJsonSchematics.migrations;
      }
      collectionPath = resolve(dirname(packageJsonPath), pkgJsonSchematics);
    }

    try {
      if (collectionPath) {
        JSON.parse(stripJsonComments(readFileSync(collectionPath).toString()));
        return collectionPath;
      }
    } catch (e) {
      throw new Error(`Invalid migration file in package: "${name}"`);
    }
    throw new Error(`Collection cannot be resolved: "${name}"`);
  }
}

class MigrationsWorkflow extends BaseWorkflow {
  constructor(host: virtualFs.Host, logger: logging.Logger) {
    super({
      host,
      engineHost: new MigrationEngineHost(logger),
      force: true,
      dryRun: false
    });
  }
}

async function runMigrations(
  logger: logging.Logger,
  root: string,
  opts: { runMigrations: string }
) {
  const migrationsFile = JSON.parse(
    stripJsonComments(readFileSync(join(root, opts.runMigrations)).toString())
  );

  const host = new virtualFs.ScopedHost(new NodeJsSyncHost(), normalize(root));
  const workflow = new MigrationsWorkflow(host, logger);
  let p = Promise.resolve(null);
  migrationsFile.migrations.forEach(m => {
    p = p.then(() => {
      logger.info(`Running migration ${m.package}:${m.name}`);
      return workflow
        .execute({
          collection: m.package,
          schematic: m.name,
          options: {},
          debug: false,
          logger
        })
        .toPromise()
        .then(() => {
          logger.info(`Successfully finished ${m.package}:${m.name}`);
          logger.info(
            `---------------------------------------------------------`
          );
        });
    });
  });

  await p;
}

export async function migrate(
  root: string,
  args: string[],
  isVerbose: boolean = false
) {
  const logger = getLogger(isVerbose);

  return handleErrors(logger, isVerbose, async () => {
    const opts = parseMigrationsOptions(args);
    if (opts.type === 'generateMigrations') {
      await generateMigrationsJsonAndUpdatePackageJson(logger, root, opts);
    } else {
      await runMigrations(logger, root, opts);
    }
  });
}